Military Communications and Information Technology: A Trusted ...

94 Military Communications and Information Technology...
• Display block.
• Data storage block.
• BITE block.
The first part of the conception is the power supply block [11], consisting
mainly from the DC/DC converter allowing the device operation in a wide input
voltage range (6-36 V) with 5 V output. This wide range allows the device to be
used in many types of aircraft. It is able to provide a voltage spikes filtering and
even independent voltage source with galvanic isolation for the purpose of the safe
bus communication. This block is basically same for every instrument.
Figure 1. Example of a gauge instrument from MESIT company
Second mentioned part is the signal processing block [11]. For signal processing
is necessary to divide them to several groups according to way of physical
principle of quantity sensing (employed sensor) and according to way of its analyzing
at measuring chain. Signals from sensors are impedance matched and eventually also
separated. Anti-aliasing filter for suppression of unnecessary spectrum part follows.
Figure 2. Example of a measurement blocks
All signals are consequently normalized, thus DC offset is cut off. By amplification
(attenuation) their magnitude is adapted to useful range of measuring
converter. Afterwards precision is given by converter bit resolution.